In order to study the influence of statistical effects on the microwave behavior of polar semiconductors, power reflection and transmission measurements have been performed onn‐type InSb with the aid of a modified reflectometer at 134 GHz in the temperature range from 83 to 170 K. The carrier concentration and the dc mobility were measured by the van der Pauw method. The Boltzmann equation was numerically solved for low dc and ac electric fields. The calculated dc mobility vs temperature curve was adjusted to the experimentally determined curve by a proper choice of the total ionized impurity concentrationNi. Using this value ofNithe power reflection and transmission at 134 GHz were calculated. Good agreement is obtained between experiment and theory, especially for the temperature dependence. It is shown that at 134 GHz the ac behavior ofn‐InSb cannot be described accurately by Drude's theory.